66 AMERICAN SPI9KRS AND THEIK SPINNINGWORK. 



This sitting position is not unusual, but is not common ; I have noticed 

 several species which appear at times to indulge in it. The attitudes of 

 the body, while substantially like those figured, vary somewhat accord- 

 ing to circumstances. Epeira vertebrata, E. arabesca, and E. benjamiiia 

 are some of the Orbweavers observed in this posture. No doubt the 

 position gives a grateful relief from the ordinary attitude, by changing 

 the direction of tension, if nothing more. 



IV. 



Under examples given in Vol. I., illustrating the physical and mechan- 

 ical powers of spiders, was a case of a small fish captured by a species of 



Dolomede or Lycosid spider. The case has excited much in- 

 r:.:!^ terest, and it is gratifying to have it supported by a like well 



Spider fiuthenticated instance. Mr. Francis R. Welsh, of Philadelphia, 



writes me that a spider once killed two sun fish, each about two 

 inches long, that he liad in a basin in his room. After having attacked 

 the first fish it ran over the water and fastened upon the second, which 

 was also at the time apparently well and vigorous. Mr. Welsh drove the 

 spider oif, but the fishes died in a few hours. The basin was kept in a 

 second story room of a country house at Chestnut Hill, and climbing vines 

 covered the outer walls, nearly approaching a window close by the basin. 

 It was inferred that the aranead entered the window from the vines. Mr. 

 Welsh could not identify the spider, and could describe it only in a general 

 way ; but judging from the figures in my books he supposed it might 

 have been either a Dolomedes or Agalena na^via. It would be entirely 

 possible for the former animal to accomplish the deed, for in the cocoon- 

 ing season Dolomedes lurks in the bushes near her egg nest (Vol. II., 

 page 145), spun among the leaves. One would hesitate, however, to think 

 of Agalena as a creature of amphibious habits. 



The same gentleman, referring to the engineering habits of spiders, as 

 described Vol. I., page 211, and especially of the use of counterpoise, tells 



me that he saw a spider one day cut a dead leaf out of its web, 

 Coun1;er- ^yi^idi was dropped and hung by several threads. It then cut it 

 Webs <^'own again twice, the leaf each time dropping and hanging lower. 



Mr. Welsh could not see if the spider attached any special threads 

 to the leaf, but she ultimately used it as a counterpoise to her snare. 



V. 



Many Orbweavers have a curious habit of moving themselves rapidl}^ 

 upon their webs when excited by any cause whicli attracts their attention 

 or awakens fear. It is particularly noticealjle in the genera Argiope and 

 Acrosoma. This action occurs when the spider is stationed at the centre 



